postcss config example

package.json

{
  "private": true,
  "scripts": {
    "css": "postcss module.css --no-map --output main.css"
  },
  "devDependencies": {
    "postcss-cli": "^4.1.1",
    "postcss-functions": "^3.0.0",
    "postcss-import": "^11.0.0"
  }
}

postcss.config.js

const swatch = require("./swatch");

module.exports = ctx => ({
  map: ctx.options.map,
  parser: ctx.options.parser,
  plugins: {
    "postcss-import": {
      root: ctx.file.dirname
    },
    "postcss-functions": {
      functions: { swatch }
    },
  }
});